Sewing machine with equipment for sewing of parallel seams

ABSTRACT

The disclosure relates to an improvement on the apparatus of U.S. Pat. No. 3,782,310 which discloses a sewing machine with an attachment for aligning two superposed layers of material to be united by one or more edge parallel seams, which comprises a series of rods to align the edges of the layers, a separating plate for the layers, and a pair of braking points positioned to cause the separate layers to pivot into alignment along the series of rods.

United States Patent 1191 Mall [4 1 Sept. 16, 1975 SEWING MACHINE WITH EQUIPMENT FOR SEWING 0F PARALLEL SEAMS [75] Inventor: Gunther Mall, Kaiserslautem,

Germany [73] Assignee: Pfaff Industriemaschinen GmbH,

Kaiserslauten, Germany [22] Filed: May 9, 1974 [21] Appl. No.: 468,428

[30] Foreign Application Priority Data May 21, 1973 Germany 1.'......2325706 [52] US. Cl. 112/153 [51] Int. Cl. D058 35/10 [58] Field of Search 112/153, 152, 150, 148,

[56] References Cited UNITED STATES PATENTS 424,010 3/l890 Locke 1 12/237 3,782,310 1/1974 Stockel 112/153 3,794,230 2/1974 Bryan et a1 112/153 X FOREIGN PATENTS OR APPLICATIONS 3,495 12/1871 United Kingdom 112/153 Primary Examiner-Wemer 1-1. Schroeder Assistant ExaminerPeter Nerbun Attorney, Agent, or Firm--Orville N. Greene; Frank L. Durr [57] ABSTRACT The disclosure relates to an improvement on the apparatus of US. Pat. No. 3,782,310 which discloses a sewing machine with an attachment for aligning two superposed layers of material to be united by one or more edge parallel seams, which comprises a series of rods to align the edges of the layers, a separating plate for the layers, and a pair of braking points positioned to cause the separate layers to pivot into alignment along the series of rods.

7 Claims, 5 Drawing Figures mgmggsemsms 3,905,316

sum 2 95 2 Fig. 4

Fig. 3

SEWING MACHINE WITH EQUIPMENT FOR SEWING OF PARALLEL SEAMS According to the present invention, means is provided to separately regulate the pressure applied to the braking or pressure points and/or means is provided to inactivate the pressure points to permit easy introduction of the layers. a

The present invention concerns a further develop ment of the sewing machine for making edge parallel seams on sewing goods layers of any contour, after U.S. Pat. No. 3,787,310, said machine having at least one material pusher or feeder and a guide means which has means for aligning two superposed layers of sewing goods fed on separate supporting plates and which guide means extends along the side of the line passing through the needle axis in the transport direction at a sharp angle thereto and wherein there is provided for each layer of goods to be sewed a pressure point situated laterally and in front of the stitch forming place.

According to the disclosure of said U.S. Pat. a sewing machine is provided with a material feeder and a guide means for the manufacture of edge parallel seams on superposed sewing goods layers, which essentially is formed of spaced superposed supporting plates for the individual layers, whereby the supporting plates, through the formation ofa pressure point for each layer of sewing goods at a place positioned laterally of and in front of the stitch-forming place, cause the layers to meed under tension. In this way, a braking or retarding effect is effected at the region of the pressure points on each individual layer of sewing goods, whereby each layer is independently guided through pivotal motion and thereby moves naturally to the alignment means which extends at a sharp angle to the line extending in the transport direction through the needle axis.

The apparatus, according to the prior U.S. Patent, offers indeed the possibility of producing edge parallel seams as well on work pieces with rectilinearly running edges as on those with curved edges, without the aid of a pattern or an aligning means for feeling out the edges of the sewing goods layers, however it is often not very easy to bring the sewing goods into a starting position for sewing the seam, i.e. between the supporting plates, as a result of the requisite biasing of the supporting plates. Also, on account of the biasing of the supporting plates, there are many difficulties in sewing over thickenings such as can occur on cross seams.

The invention improves the apparatus of the prior U.S. Patent in that layers of sewing goods which have thickenings can be guided without difficulties and in that the insertion of the goods to be sewed, is facilitated. These problems are solved according to the invention by holding both of the superposed layers of sewing goods for the production of parallel seams on a separating plate by means of positively connected, adjacent, pressure means. and by providing independent means to control each of the pressure means and to in' dependently move each of the pressure means to an inoperative position.

This arrangement opens up the possibility, not only at the beginning of a seam, but also upon seam crossings, for temporarily withdrawing both pressure means to an inoperative position through independently adjustable members and thereby reduce or completely lift-offthe force on the pressure means for a short time.

Another possibility for the solution of the problems, when employing a separating plate provided with pressure applying upper and lower thickenings for the two layers and a covering plate substantially parallel to the separating plate, is provided by pivotally mounting said two plates and providing means for moving each of said plates to an inoperative position.

From the constructive viewpoint, an especially simple solution to the lifting of the upper pressure means can be obtained when said upper pressure means is mounted on the arm of a lever-like carrier pivotally mounted on a horizontal axle, in which the arm opposite the pressure means is engaged by a control element which is slidably supported and has a slanting surface.

As a way of moving or releasing the lower pressure means, it is advantageous to slidably mount the latter in a guide bushing fastened to the base plate of the machine parallel to the axis of the needle and having a cross rod at its lower end to allow it to cooperate with a slidably guided control means having a slanted surface.

For adjusting the pressure on the upper pressure means according to another feature of the invention having the adjustable thrust means at one end, a charging spring is provided at the other side of the lever-like carrier device.

In order to be able to adjust the pressure of the lower pressure means, it is convenient to provide a spring within the guide bushing thereof, which is held at one end by a cross piece on the pressure means and at the other end is supported by an adjustable abutment.

In the following description, the invention will be described in more detail in connection with the embodiments thereof shown in the accompanying drawing. In the drawing:

FIG. 1, is a front view of a first embodiment of the guide apparatus of the invention, is shown with the arm of a sewing machine.

FIG. 2 is a plan view of intermediate area of the stitch forming part ofa sewing machine and device of FIG. 1.

FIG. 3 is a front view of a second embodiment of the apparatus of the invention.

FIG. 4 is an enlarged detail view of the portion A of FIG. 3.

FIG. 5 is a plan view of the intermediate area of the stitch forming place of a second embodiment.

The FIGS. 12 device is shown together with the arm 1 of a sewing machine, which has a looper cooperating with needle 2, a lower material feeder 3 and a pressure foot 4.

On the base plate 5 of the sewing machine, a plate 6, having its forward end rounded off is arranged, on which a spacer 7 is fastened. The thickness of spacer 7 is somewhat greater than the maximum thickness of the lower layer of goods to-be-sewed 9. The lateral side 8 of the spacer 7 which faces the needle serves as a guide edge for the lower layer of goods to be sewed and develops, as especially obvious from FIG. 2, in front of the stitch forming place at a sharp angle to the feed direction in order that the goods will be parallel to the feed direction on reaching the immediate area of the stitch forming means.

Above the spacer 7, separating plate 11 for the two layers of goods 9, l0 to-be-sewed is arranged, which extends in the plane parallel to the plate 6. On the separating plate 11, an upper spacer 12 is provided, which likewise is somewhat thicker than the maximum thickness of the upper layer of goods 10.

The needle facing surface 13 of the spacer 12 serves as a guide edge for the upper layer of goods 10 and develops a sharp angle in front of the stitch forming place with respect to the feed direction of the goods to-besewed, and then extends in the immediate area of the stitch forming place parallel to the feed direction.

Above the upper spacer 12 is arranged a plate 14 serving as a guard for the upper layer to be sewed 10, which, for easy introduction of said upper layer 10, is turned up at its nearer edge, as viewed in FIG. 1. The three plates 6, 11 and 14, as well as both of the intermediate spacers 7 and 12, are securely connected by penetrating screws with the carrier plate 15, which is adjustably fastened to the base plate of the sewing machine.

The pressure means 16 serves to apply pressure to the upper layer of sewing goods and is formed with a dome-shaped end for contacting said layer of sewing goods, said means 16 projecting through the slot-like recess 17 of plate 14. The pressure means 16 is fastened to the arm 18 of lever carrier 19, which is pivotally mounted on a horizontal axis.

The plug screw 21 serves to seat the lever 19, the screw 21 being mounted in a bearing flange 22 of support 23, which is adjustable arranged on the carrier plate 15. Adjacent the arm 20, opposite the pressure means 16 oflever 19, is a piston rod 24 of compressed air cylinder 25, which carries, at its forward end, a lever stick 27 having a sloping surface 26 so that sliding movement of the lever stick 27 will pivot the lever 19 about the screw journal 21. For adjusting the pressure between pressure means 16 and said upper layer 10, the arm of lever 19 is held suspended at one end with a spring 28, fastened at its upper end to a threaded rod 29. The threaded rod 29 is guided on a flange 30 of carrier means 23 and can be adjusted by means of a knurled screw 31.

The pressure means 32 serves to apply pressure to the lower layer 9 of sewing goods and is slidably retained in the guide sleeve 33 which is screwed into the base plate 5. The goods-contacting end of the pressure means 32 is also dome-shaped and it projects upwardly through the base plate 5. Adjacent its lower end, the pressure means 32 carries a cross-piece 34 which cooperates with the piston 34 of compressed air cylinder 36 and the fork shaped end 37 with the sloping surface 38 on the under side thereof.

In order to provide for adjustment of the compressive force of the lower pressure means 32, the latter is provided with a second cross piece 39 which slides in a slotted recess 40 of the guide sleeve 33. Against the cross piece 39, one end of a spring 41 abuts, the other end thereof abutting against the screwable adjusting nut 42, so that a change in the screwed'in-depth of the nut 42 changes the force on pressure means 32.

The making of an edge parallel seam is accomplished as follows:

The lower of the two layers 9, 1O to-be-sewed together (which can have any chosen outline form), is placed on plate 6, while the upper layer 10 is supported on separating plate 11. During the insertion procedure. the two pistons 24 and 35 of cylinders 25, 36 are in their projected position so that the upper pressure means 16 is lifted to an inoperative position and the lower pressure means 32 is withdrawn to its inoperative position.

After the insertion of both layers 9 and 10, the pistons 24 and 35 are retracted so that the pressure means 16 and 32 are released. The upper pressure means 16 presses the upper layer 10 against the upper side of separating plate 11, while the lower pressure means 32 presses the lower layer 9 against the underside of separating plate 11. Both layers 9 and 10 are permitted to pass between the plates 14 and 6, however, in the area of the pressure means, a retarding or braking action is exerted thereon.

The front edges of the goods to be sewed are placed edge on edge by the operator and are then positioned under the needle 2. The initial stitches are sewed in the usual way. During the formation of the next stitches, the material feeder 3 exerts a pulling force on the layers in the feed direction and imparts to the layers, the usual feeding movement. Through the action of the pulling force, and the retarding action of the pressure means 16, 32 each layer is subjected to a pivoting movement around an axis parallel to the needle axis, whereby, due to the fact that the two layers are separated by the separating plate 11 and that the braking'action of the pressure means 16, 32 is adjustable, the pivoting movement of the upper layer 10 is independent of the pivoting movement of the lower layer 9.

Through the pivoting movements, the edges of each layer rotate until brought linearly along the limiting surfaces 8, 13 of spacers 7, 12 and thereafter move along the same. Botth layers come independently with respect to one another into alignment on the apparatus to be rectified thereby and in continuing the process move with parallel edges to the stitch forming posistion.

In order to sew over a thickening, as, for example, through a cross-seam in the upper layer, the upper pressure means 16 is momentarily lifted to an inoperative position through movement of piston 24. As soon the thickening has passed the area of pressure means 16, the lever 18 is released and the pressure means 16 returns to its operating position. The upper layer will, as long as the lever 18 occupies its inoperative position, not be pivoted to its accompanying linear position, but it has been found that the momentary interruption of the guide control of the layer brings no variation in the seam form. I

The embodiment shown in FlGS. 3 and 4 comprises a carrier plate fastened to base plate 5 of the sewing machine, in which a separating plate 51 for extending between two layers of goods to-be-sewed as well as a cover plate 52 for the upper layer are supported by means of two pivotally mounted hinges 53 and 54, respectively.

The separating plate 51 (FIG. 3) is provided on both sides with dome-shaped thickenings whereby the lower thickening 55 forms a pressure contact means for the lower layer and the upper thickening 56 a pressure contact means for the upper layer of goods to-besewed. Both superposed thickenings correspond to those of said prior patent in being arranged laterally of the needle 2 and in front of the stitch forming region.

Analogous to the development described in the prior patent, a plurality pegs 57 (see FIG. 5) arranged one after the other and fastened to the carrier plate 50 serve as the linear edge guide for the layers to-besewed. The pegs 57 penetrate the separating plate 51 as well as the upper plate 52 and are arranged in a straight line which passes laterally of and at a sharp angle to a line passing through the needle axis in the feed direction. A guide means 76 fastened on the base plate 5 of the sewing machine is arranged after the pegs 57 and is so constructed that the front part 78 thereof in front of the material feeder is tangent to the pegs 57 to form a stitch forming line for the side edge 77, while the part 79 thereof extends laterally of the material feeder and parallel to the feeding direction of the sewing goods j ,1

Below the base plate 5 of the sewing machine, a first compressed air cylinder 58 is arranged whose piston 59 projects through the base plate 5 and the carrier plate 50 and which abuts the underside of the separating plate 51. Laterally of this pressure cylinder 58, a second air pressure cylinder 60 is provided whose piston 61 projects through the base plate 5, the carrier plate 50, and the separating plate 51, and which abuts the lower side of plate 52.

The strokes of pistons 59, 61 of the two pressure cylinders 58, 60 are so chosen that the piston 61 executes a greater stroke than piston 59. Thereby, there is attained, by the simultaneous movement of both pistons, a greater span of movement for plate 52 than for separating plate 51, so that the plate 52 will be lifted off of the thickening 56 of the separating plate 51 and the thickening 55 of plate 51 will be lifted off carrier plate 50 as well, whereby the available passing space be tween plates 50, S1 and 51, 52, respectively, is enlarged.

In order to adjust the pressure of separating plate 5.1' or the thickening 55 against carrier plate 50, the separating plate 51 has a nipple 62 thereon which projects through clearance 63 in plate 52 andis provided with outer screw threads. On the nipple 62, a screw cap 64 is threaded, which has a rod 65 slidably arranged in boring 66, adapted to pass through nipple 62. The rod 65 guided in nipple 62 braces itself with its lower end against carrier plate 50 and carries a shoulder 67 which serves as an abutment for spring 68 surrounding rod 65. The spring 68 has one end resting against shoulder 67 and the other end thereof on the screw cap 64, so that the pressure exerted between separating plate 51 and the carrier plate 50 can be changed by adjusting the screw cap 64.

For adjusting the pressure of the upper plate 52, it also is provided with a nipple 69 which carries a screw cap 70. The rod 73 projects through the boring of nipple 69, the boring 71 of separating plate 51 and the boring 72 of nut 70 and thereby rests on carrier plate 50. Also, the rod 73 carries a shoulder 74 for a surrounding spring 75, the other free end of which rests in the screw cap 70. By changing the depth that screw cap 70 is screwed onto nipple 69, the pressure between the separating plate 51 and the plate 52 is changed.

The second embodiment of the invention operates as follows:

For the insertion of the goods to-be-sewed, both piston rods 59, 61 are extended, whereby, because of the difference in strokes of the piston rods, the plate 52 swings a greater amount about the axis of its hinge 54 than the separating plate 51. Thus, the plate 52 is lifted off of the thickening 56 of separating plate 51, and also the thickening 55 of separating plate 51 is lifted off of carrier plate 50.

Both layers of sewing goods can now be introduced, the lower layer resting on support plate 50 and the upper layer on the separating plate 51. Thereafter, piston rods 59, ,61 are retracted, whereupon thickening 55 forms a press point for the lower layer which thickening 56 cooperates with the upper plate 52 to form a pressure point for the upper layer. The depths to which caps 64, are screwed. and the dead weight of the separating plate 51, as well as the plate 52, are so chosen that both layers of goods to be sewed can be converged between the plates 50, 51 and 52, while the retarding force exerted on the layers during the sewing process independently align the layers along the pegs 57.

If a seam thickening occurs on the lower goods layer,

.the piston rod 59 is extended a predetermined amount to lift the separating plate 51 off of the carrier plate. The sewing goods layer with a seam thickening, as for example, one formed by a cross-seam, can be passed through the area of the pressure point without infavorably influencing the guiding process. By lifting the separating plate 51, the pressure between the latter and the upper plate 52 will indeed be somewhat increased, however, it hass become evident that such an unimportant increase of the pressure for guiding the upper layer is ordinarily not disturbing and, if necessary, can easily be balanced by lifting the upper plate 32 with the aid of piston rod 61 of pressure cylinder 60.

Each of the embodiments of the invention, accordingly' assure that upon the appearance of a'thickening on a sewing goods layer,'a feeler, which is arranged an adequate distance in front of the pressure points, can

determine the thickening and reduce the pressure cor responding to the thickening by movement of the pres plates'Sl, 52 (FIGS. 3-4).

I claim:

1. In a sewing machine for sewing edge parallel seams on upper and lower superposed layers of sewing goods of any contour, of the type having a stitching plac e comprising at least one needle and at least one material feeder, supporting plates for the two layers including a seaparating plate for maintaining the two layers in spaced relation positioned in front of the stitching position and including a plate covering the separating plate, guide means for the two layers extending laterally of and at a sharp angle to the line running through the needle axis in the feed direction, and a pair of pressure means, one for the upper layer and one for the lower layer, for applying pressure to the separate layers at points in front of and laterally of the stitching position for aligning the layers along the guide means, the improved construction comprising a first adjustable spring means adapted to control the pressure applied by the upper pressure means to the upper layer, a second adjustable spring means adapted to control the pressure applied by the lower pressure means to the lower layer, a first inactivating means for independently inactivating the upper pressure means without affecting the pressure applied to the lower pressure means and a second inactivating means for independently inactivating the lower pressure means without affecting the pressure applied to the upper pressure means.

2. In a sewing machine for sewing edge parallel seams on two superposed layers of sewing goods of any contour, of the type having a stitching place comprising at least one needle and at least one material feeder, supporting plates for the two layers including a separating plate for maintaining the two layers in spaced relation positioned in front of the stitching position, guide means for the edges of the two layers extending laterally of and at a sharp angle to the line running through the needle axis in the feed direction, and a pair of pressure means, one for the upper layer and one for the lower layer for applying pressure to the separate layers at points in front of and laterally of the stitching position for aligning the layers along the guide means, the improved construction wherein the pair of pressure means for applying pressure to the layers comprise separately controlled upper and lower means for pressing the respective layers against the separating plate, a first inactivating means for independently inactivating the upper pressing means without affecting the pressure applied to the lower pressing means, and a second inactivating means for independently inactivating the lower pressing means without affecting the pressure applied to the upper press-means 3. The sewing machine as claimed in claim 2 wherein said upper pressure means comprises a lever device with a pressure applying means at one end, an intermediate fulcrum and shiftable means for operating the opposite end of the lever to inactivate the pressure applying means.

4. The sewing machine as claimed in claim 2 wherein the lower pressure means comprises a rod, guide sleeve means for shiftably mounting the rod to move parallel to the needle axis toward the separating plate, a crosspieceon the lower end of said rod, and shiftable means with a sloping surface adapted to cooperate with said cross-piece to inactivate said lower pressure means.

5. The sewing machine as claimed in claim 3, comprising adjustable spring tensioning means adapted to normally urge the upper pressure means towards the separating plate.

6. The sewing mmachine as claimed in claim 4 comprising spring means between said rod and said guide sleeve adapted to urge the rod towards said separating plate, and screw means for adjusting the force on said spring.

7. In a sewing machine for sewing edge parallel seams on two superposed layers of sewing goods of any contour, of the type having a stitching place comprising at least one needle and at least one material feeder, supporting plates for the two layers including base plate and a separating plate for maintaining the two layers in spaced relation posistioned in front of the stitching position, guide means for the edges of the two layers extending laterally of and at a sharp angle to the line running through the needle axis in the feed direction, said separating plate having upper and lower thickenings, one on each side thereof, at a point in front of and laterally of the stitching position for aligning the layers along the guide means, and including a cover plate covering the separating plate against which the upper thickening is adapted to bear, the improved construction comprising a first pressure adjusting means carried by said separating plate adapted to adjust the pressure applied between the lower thickening of the separating plate and the base supporting plate, a second pressure adjusting means carried by said cover plate adapted to adjust the pressure applied between the cover plate and the upper thickening of the separating plate, means for pivotally mounting the separating plate, means for pivotally mounting the cover plate, means adapted to pivot the cover plate away from the separating plate, separate means adapted to pivot the separating plate away from the base plate, whereby both plates can be pivoted to a position permitting easy insertion of the layers to be sewed and either plate may be pivoted separately without affecting the pressure applied between the other plate and the respective thickening of the separating plate. 

1. In a sewing machine for sewing edge parallel seams on upper and lower superposed layers of sewing goods of any contour, of the type having a stitching place comprising at least one needle and at least one material feeder, supporting plates for the two layers including a seaparating plate fOr maintaining the two layers in spaced relation positioned in front of the stitching position and including a plate covering the separating plate, guide means for the two layers extending laterally of and at a sharp angle to the line running through the needle axis in the feed direction, and a pair of pressure means, one for the upper layer and one for the lower layer, for applying pressure to the separate layers at points in front of and laterally of the stitching position for aligning the layers along the guide means, the improved construction comprising a first adjustable spring means adapted to control the pressure applied by the upper pressure means to the upper layer, a second adjustable spring means adapted to control the pressure applied by the lower pressure means to the lower layer, a first inactivating means for independently inactivating the upper pressure means without affecting the pressure applied to the lower pressure means and a second inactivating means for independently inactivating the lower pressure means without affecting the pressure applied to the upper pressure means.
 2. In a sewing machine for sewing edge parallel seams on two superposed layers of sewing goods of any contour, of the type having a stitching place comprising at least one needle and at least one material feeder, supporting plates for the two layers including a separating plate for maintaining the two layers in spaced relation positioned in front of the stitching position, guide means for the edges of the two layers extending laterally of and at a sharp angle to the line running through the needle axis in the feed direction, and a pair of pressure means, one for the upper layer and one for the lower layer for applying pressure to the separate layers at points in front of and laterally of the stitching position for aligning the layers along the guide means, the improved construction wherein the pair of pressure means for applying pressure to the layers comprise separately controlled upper and lower means for pressing the respective layers against the separating plate, a first inactivating means for independently inactivating the upper pressing means without affecting the pressure applied to the lower pressing means, and a second inactivating means for independently inactivating the lower pressing means without affecting the pressure applied to the upper press-means
 3. The sewing machine as claimed in claim 2 wherein said upper pressure means comprises a lever device with a pressure applying means at one end, an intermediate fulcrum and shiftable means for operating the opposite end of the lever to inactivate the pressure applying means.
 4. The sewing machine as claimed in claim 2 wherein the lower pressure means comprises a rod, guide sleeve means for shiftably mounting the rod to move parallel to the needle axis toward the separating plate, a cross-piece on the lower end of said rod, and shiftable means with a sloping surface adapted to cooperate with said cross-piece to inactivate said lower pressure means.
 5. The sewing machine as claimed in claim 3, comprising adjustable spring tensioning means adapted to normally urge the upper pressure means towards the separating plate.
 6. The sewing mmachine as claimed in claim 4 comprising spring means between said rod and said guide sleeve adapted to urge the rod towards said separating plate, and screw means for adjusting the force on said spring.
 7. In a sewing machine for sewing edge parallel seams on two superposed layers of sewing goods of any contour, of the type having a stitching place comprising at least one needle and at least one material feeder, supporting plates for the two layers including base plate and a separating plate for maintaining the two layers in spaced relation posistioned in front of the stitching position, guide means for the edges of the two layers extending laterally of and at a sharp angle to the line running through the needle axis in the feed direction, said separating plate havinG upper and lower thickenings, one on each side thereof, at a point in front of and laterally of the stitching position for aligning the layers along the guide means, and including a cover plate covering the separating plate against which the upper thickening is adapted to bear, the improved construction comprising a first pressure adjusting means carried by said separating plate adapted to adjust the pressure applied between the lower thickening of the separating plate and the base supporting plate, a second pressure adjusting means carried by said cover plate adapted to adjust the pressure applied between the cover plate and the upper thickening of the separating plate, means for pivotally mounting the separating plate, means for pivotally mounting the cover plate, means adapted to pivot the cover plate away from the separating plate, separate means adapted to pivot the separating plate away from the base plate, whereby both plates can be pivoted to a position permitting easy insertion of the layers to be sewed and either plate may be pivoted separately without affecting the pressure applied between the other plate and the respective thickening of the separating plate. 